1.That cute little puppy has (stole, stolen) a biscuit.
2.The Boys Choir of Harlem has never (sang, sung) more beautifully.
3.Jimmy's toy sailboat had (sank, sunk) to the bottom.
4.Why had the dog (took, taken) the cell phone outside?
5.Why have all those people (swam, swum) across the English Channel?